Immunodeifciencys Flashcards
What are immunodeficiency’s?
Caused by defects in immune system components
May lead too seriously an often fatal syndromes or diseases
Classified as primary and secondary
Difficult to estimate at birth
What are PRIMARY (congenital) immunodeficiency’s (PID)?
A condition resulting from a genetic or developmental defect
Defect present FROM BIRTH n it mostly inherited
May not be observed NTS later in life
What are SECONDARY immunodeficiency’s?
Reignite as a result of malnutrition, cancer, drug treatment or infection
By far the most well known and commonly occurring is AIDS
What are the lineal features of primary immunodeficiency’s?
Reaccurent infections
Severe infections, unusual pathogen (that wont usually cause a immune response) , unusual sites
There are 10 warning signs - 2 or more indicate PID
What causes PID?
May effect either innate or adaptive immune function
Defects in innate immunity are generally caused by a defect in phagocytise or complement function.
Lymphoid cell disorders may effect T cells or B cells
What is the relation between PID and haematopoesis?
Defects in the earlier stem cells affect the entire Immune system
Defects in later stage haematopoietic cells show a more restricted pathology
REVISION ACTIVITY
DRAW A TREE DIAGRAM FROM THE SLIDE IN THE LECTURE OF HAEMATOPPOEIISIS AND MAKE. MIND-MAP LINKING THE CELLS WTH OTHER LECTURES AND THE FUNCTIONS OF EACH COLOUR GROUP OF CELLS
What are the defects in adaptive immunity that can cause PID?
B cells, T cells combined
T cell defects impair antibody function
Defects in lymphocyte development or activation
What are the major B cell disorder of PID?
Brutons disease (x linked a gamma globulin anaemia)
Common variable deficiency (CVID)
Selective IgA deficiency
igG2 subclass deficiency
Specific ig deficiency with normal igs
What is Brutons disease?
Defect in BTK gene. - located on X chromosome
Encodes Britons tyrosine kinase - important in signalling downstream pre-B cell receptor too become mature B cells
Bock in B-cell development when gene is mutated
Reaccurant severe bacterial infections
35% develop autoimmune conditions
How is Brutons disease diagnosed?
B cells abscent/ low; plasma cells abscent
All immunoglobulins abscent / very low
T cells and T cell-mediated responses normal
Diagnosed using immunoelectrophoresis an flow cytometry
How is Brutons disease treated?
IVIg
OR subcutaneous Ig weekly
Prompt antibiotic therapy (URI/LRI)
Do not give live-attenuated vaccines
What is igA selective deficiency?
Most common
Most cases asymptomatic; some infections of Respiratory, urogenital or gastrointestinal
Low levels serum and secretory igA
Sometimes increased incidence allergic disease
What is combined immunodeficiency’s?
Severe combined immunodeficiency (SCID)
- immmnoglobids are low
- affect T,B NK cells
- T cell function reduced and cytokine production
Predominant T cell disorders.
What causes severe combined immunodeficiency SID?
Common cytokine receptor gamma chain defect (IL-2, IL-4, IL-7).
IL-7 needed for survival T cell precursors resulting in defective T cell development and concomitant lack in B cell help (low antibodies)
RAG-1/RAG-2 defect = no T and B cells
ADA = cumulative of deoxyadenosine + deoxy-ADP which is toxic for rapidly dividing thymocytes
IL-2 important for cytotoxic T cell survival
